Showing papers on "Offset (computer science) published in 2013"

Method for operating a laser scanner

Abstract: A method for operating an indicia reader such as a laser scanner is provided. The method affords a simplified technique for monitoring the offset between the drive frequency and the resonant oscillation frequency of the laser scanner. The phase offset between the drive frequency and the sense frequency is monitored to derive the drive frequency's offset from the resonant oscillation frequency.

A Low-Power High-Precision Comparator With Time-Domain Bulk-Tuned Offset Cancellation

Abstract: A novel time-domain bulk-tuned offset cancellation technique is applied to a low-power high-precision dynamic comparator to reduce its input-referred offset with minimal additional power consumption and delay. The design has been fabricated in a commercially available 0.5-μm process. Measurement results of 10 circuits show a reduction of offset standard deviation from 5.415 mV to 50.57 μV, improved by a factor of 107.1. The offset cancellation scheme does not introduce observable offset or noise, and can achieve fast and robust convergence with a wide range of common mode input. Operating at a supply of 5 V and clock frequency of 200 kHz, the comparator together with the OC circuitry consumes 4.65 μW of power, or 23 pJ of energy per comparison.

Kinematic road gradient estimation

Abstract: A vehicle and a vehicle system are provided with a controller that is configured to generate output indicative of a kinematic road gradient estimation using an extended Kalman filter. The extended Kalman filter includes a system input based on a longitudinal acceleration and an acceleration offset, and a system output based on a predicted vehicle speed. The acceleration offset is based on at least one of a lateral velocity, a lateral offset, and a vehicle pitch angle. The controller is further configured to generate output indicative of a kinematic quality factor corresponding to an availability of the kinematic road gradient estimation.

Vehicle yaw rate correction

Abstract: A control system or method for a vehicle references a camera and sensors to determine when an offset of a yaw rate sensor may be updated. The sensors may include a longitudinal accelerometer, a transmission sensor, a vehicle speed sensor, and a steering angle sensor. The offset of the yaw rate sensor may be updated when the vehicle is determined to be stationary by referencing at least a derivative of an acceleration from the longitudinal accelerometer. The offset of the yaw rate sensor may be updated when the vehicle is determined to be moving straight by referencing at least image data captured by the camera. Lane delimiters may be detected in the captured image data and evaluated to determine a level of confidence in the straight movement. When the offset of the yaw rate sensor is to be updated, a ratio of new offset to old offset may be used.

Time-series deformation monitoring over mining regions with SAR intensity-based offset measurements

Abstract: Underground mining can induce large vertical displacements that often lead to the loss of coherence in repeat-pass interferometric synthetic aperture radar (SAR) images. Using SAR intensity images, this paper employs the image offset tracking method to map SAR slant range changes due to ground deformation over areas of mining. The rationale of slant range offset measurement with respect to the vertical deformation is analysed and the prerequisite of applying the slant range offset method to monitor vertical deformation is discussed. Results from the slant range offset method are used to produce time-series of cumulative ground displacements via least square estimate. We use six Advanced Land Observation Satellite (ALOS)-Phased Array L-band SAR (PALSAR) images over two coalfields in Inner Mogolia, China, to illustrate the proposed method and its effectiveness. We achieve deformation measurements with a precision of ∼0.2 m, with the maximum vertical displacement over the mining sites reaching ∼4.5 m. Finall...

Reducing error rates for touch based keyboards

Abstract: The present technology provides systems and methods for reducing error rates to data input to a keyboard, such as a touch screen keyboard. In one example, an input bias model dynamically changes the keyboard functionality such that the keyboard will not necessarily produce the same result for an identical tap coordinate. Rather, the keyboard functionality is adapted to account for key offset bias that occurs when the user has a tendency to select a tap coordinate that would otherwise return an unintended key. Additionally, the present technology provides a language feedback model that may provide a probability for a next tap coordinate and may augment the key corresponding to the most probable next tap coordinate, thereby allowing the user to more easily select the correct key. Further details are provided herein.

Disk drive accounting for sinusoidal offset between heads when executing a rotational position optimization algorithm

Abstract: A disk drive is disclosed wherein a radial offset is measured between a first head and a second head at a plurality of points along a circumference of a corresponding first and second disk surface to generate a first plurality of radial offsets. A first radial offset is determined and a second radial offset is determined based on the first plurality of radial offsets, wherein the first radial offset corresponds to approximately a maximum in the first plurality of radial offsets and the second radial offset corresponds to approximately a minimum in the first plurality of radial offsets. A plurality of access commands are stored in a command queue, and a rotational position optimization (RPO) algorithm is executed to select a next access command to execute from the command queue, wherein the RPO algorithm is responsive to the first and second radial offsets.

SMART-Signal Phase II: Arterial Offset Optimization Using Archived High-Resolution Traffic Signal Data

Abstract: Traditionally, offset optimization for coordinated traffic signals is based on average travel times between intersections and average traffic volumes at each intersection, without consideration of the stochastic nature of field traffic. Using the archived high-resolution traffic signal data, this project developed a data-driven arterial offset optimization model that will address two well-known problems with vehicle-actuated signal coordination: the early return to green problem and the uncertain intersection queue length problem. To account for the early return to green problem, the authors introduce the concept of conditional distribution of the green start times for the coordinated phase. To handle the uncertainty of intersection queue length, the authors adopt a scenario-based approach that generates optimization results using a series of traffic-demand scenarios as the input to the offset optimization model. Both the conditional distributions of the green start times and traffic demand scenarios can be obtained from the archived high-resolution traffic signal data. Under different traffic conditions, queues formed by side-street and main-street traffic are explicitly considered in the derivation of intersection delay. The objective of this model is to minimize total delay for the main coordinated direction and at the same time it considers the performance of the opposite direction. Due to model complexity, a genetic algorithm is adopted to obtain the optimal solution. The performance of the optimized offsets are tested not only in a simulated environment but also in the field. Results from both experiments show that the proposed model can reduce travel delay of coordinated direction significantly without compromising the performance of the opposite approach.

Effects of visual conflicts on 3D selection task performance in stereoscopic display environments

Abstract: Mid-air direct-touch interaction in stereoscopic display environments poses challenges to the design of 3D user interfaces. Not only is passive haptic feedback usually absent when selecting a virtual object displayed with positive or negative parallax relative to a display surface, but such setups also suffer from inherent visual conflicts, such as vergence/accommodation mismatches and double vision. In particular, if the user tries to select a virtual object with a finger or input device, either the virtual object or the user's finger will appear blurred, resulting in an ambiguity for selections that may significantly impact the user's performance. In this paper we evaluate the effect of visual conflicts for mid-air 3D selection performance within arm's reach on a stereoscopic table with a Fitts' Law experiment. We compare three different techniques with different levels of visual conflicts for selecting a virtual object: real hand, virtual offset cursor, and virtual offset hand. Our results show that the error rate is highest for the real hand condition and less for the virtual offset-based techniques. However, our results indicate that selections with the real hand resulted in the highest effective throughput of all conditions. This suggests that virtual offset-based techniques do not improve overall performance.

A robust 2D point-sequence curve offset algorithm with multiple islands for contour-parallel tool path

Abstract: An offset algorithm is important to the contour-parallel tool path generation process. Usually, it is necessary to offset with islands. In this paper a new offset algorithm for a 2D point-sequence curve (PS-curve) with multiple islands is presented. The algorithm consists of three sub-processes, the islands bridging process, the raw offset curve generation and the global invalid loops removal. The input of the algorithm is a set of PS-curves, in which one of them is the outer profile and the others are islands. The bridging process bridges all the islands to the outer profile with the Delaunay triangulation method, forming a single linked PS-curve. With the fact that local problems are caused by intersections of adjacent bisectors, the concept of stuck circle is proposed. Based on stuck circle, local problems are fixed by updating the original profile with the proposed basic rule and append rule, so that a raw offset curve can be generated. The last process first reports all the self-intersections on the raw offset PS-curve, and then a procedure called tree analysis puts all the self-intersections into a tree. All the points between the nodes in even depth and its immediate children are collected using the collecting rule. The collected points form the valid loops, which is the output of the proposed algorithm. Each sub-process can be complete in near linear time, so the whole algorithm has a near linear time complexity. This can be proved by the examples tested in the paper.

GPU-based offset surface computation using point samples

Abstract: We present an efficient algorithm to perform approximate offsetting operations on geometric models using GPUs Our approach approximates the boundary of an object with point samples and computes the offset by merging the balls centered at these points The underlying approach uses Layered Depth Images (LDI) to organize the samples into structured points and performs parallel computations using multiple cores We use spatial hashing to accelerate intersection queries and balance the workload among various cores Furthermore, the problem of offsetting with a large distance is decomposed into successive offsetting using smaller distances We derive bounds on the accuracy of offset computation as a function of the sampling rate of LDI and offset distance In practice, our GPU-based algorithm can accurately compute offsets of models represented using hundreds of thousands of points in a few seconds on a GeForce GTX 580 GPU We observe more than 100 times speedup over prior serial CPU-based approximate offset computation algorithms

Arterial offset optimization using archived high-resolution traffic signal data

Abstract: Traditionally, offset optimization for coordinated traffic signals is based on average travel times between intersections and average traffic volumes at each intersection, without consideration of the stochastic nature of field traffic. Using the archived high-resolution traffic signal data, in this paper, we develop a data-driven arterial offset optimization model which will take two well-known problems with vehicle-actuated signal coordination into consideration: the early return to green problem and the uncertain intersection queue length problem. To account for the early return to green problem, we introduce the concept of conditional distribution of the green start times for the coordinated phase. To handle the uncertainty of intersection queue length, we adopt a scenario-based approach that generates optimal offsets using a series of traffic demand scenarios as the input to the optimization model. Both the conditional distributions of the green start times and traffic demand scenarios can be obtained from the archived high-resolution traffic signal data. Under different traffic conditions, queues formed by side-street and main-street traffic are explicitly considered in the derivation of intersection delay. The objective of this offset optimization model is to minimize total delay for the main coordinated direction and at the same time it considers the performance of the opposite direction. Due to the model complexity, a genetic algorithm is adopted to obtain the optimal solution. The proposed methodology was tested on a major arterial (TH55) in Minnesota. The results from the field implementation show that the proposed model can reduce travel delay of coordinated direction significantly without compromising the performance of the opposite approach.

Methods and related systems of building models and predicting operational outcomes of a drilling operation

Abstract: Building models and predicting operational outcomes of a drilling operation. At least some of the illustrative embodiments are methods including: gathering sensor data regarding offset wells and context data regarding the offset wells, and placing the sensor data and context data into a data store; creating a reduced data set by identifying a correlation between data in the data store and an operational outcome in a drilling operation; creating a model based on the reduced data set; and predicting the operational outcome based on the model.

Location Estimation of a Mobile Device in a UMTS Network

Abstract: The present disclosure provides devices, systems, and methods to utilize relative timing offset information reported by one or more mobile devices. When coupled with AGPS information reported by one or more mobile devices, the offset information is be used to calibrate calculations and subsequently to locate all 3G mobiles with GPS-like accuracy, whether or not a GPS receiver is available on said mobile device being located. A determination of a propagation delay between one or more cell sites and a mobile device is reported to a network and used to calibrate unknown information such as a timing offset, to improve the accuracy of a detected location. The relative timing offset can be applied to determine a location for all other mobile devices within the area served by the known base station. The present disclosure utilizes this method in conjunction with information crowd-sourced from a plurality of mobile devices.

Variable-size flash translation layer

Abstract: A method for using a variable-size flash translation layer is disclosed. Step (A) receives a read request to read data corresponding to a logical block address from a nonvolatile memory. Step (B) reads a particular entry of a map to obtain (i) a physical address of a particular page of the nonvolatile memory, (ii) an offset in the particular page to compressed data previously stored and (iii) a length of the compressed data. The particular entry is associated with the logical block address. Step (C) converts the offset and the length to (i) an address of a given read unit in the particular page and (ii) a number of the read units to be read. Step (D) reads from the particular page at most the number of the read units starting from the given read unit. An offset and length granularity are finer than one read unit.

Disk drive employing a temperature dependent write offset

Abstract: A disk drive is disclosed comprising a disk, and a head actuated over the disk, the head comprising a read element radially offset from a write element. A temperature is measured, and an operating write offset is generated based on the measured temperature. Data is written to a target radial location on the disk by radially offsetting the write element based on the operating write offset. An operating read offset is generated based on the target radial location on the disk, and the data is read from the disk by radially offsetting the read element based on the operating read offset.

Offset Lines in Doherty Power Amplifiers: Analytical Demonstration and Design

Abstract: A theoretical validation of the offset lines method for design of Doherty power amplifiers is presented for the first time. The analysis is carried out considering the simplified unilateral active device model classically adopted in Doherty amplifier theory. In particular, it is proved that, in narrow band conditions, properly designed offset lines preserve the ideal load modulation across the full power sweep range. The demonstration is independent from the Doherty strategy adopted, e.g., in terms of output power back-off, even or uneven architecture. A simple analytical formula to calculate the proper length of the lines is given, and validated through a simulation example.

Read level adjustment using soft information

Abstract: A method for calibrating read levels in a flash memory device is provided. The method includes receiving read information from flash memory in response to a read command, assigning soft information to the received read information, determining an error signal based on the assigned soft information, determining a read level offset based on the error signal, and adjusting a read level in the flash memory by the determined read level offset.

Transitioning from envelope tracking to average power tracking

Abstract: An envelope tracking power supply and an offset capacitive element are disclosed. The offset capacitive element is coupled between a switching output and an analog output of the envelope tracking power supply, which operates in one of an envelope tracking mode, a transition mode, and an average power tracking mode. During the envelope tracking mode, the envelope tracking power supply provides an envelope power supply signal using both the switching output and the analog output. During the transition mode, the envelope tracking power supply drives a voltage across the offset capacitive element from a first voltage to a second voltage, such that during a transition from the envelope tracking mode to the transition mode, the offset capacitive element has the first voltage, and during a transition from the transition mode to the average power tracking mode, the offset capacitive element has the second voltage.

Simultaneous common-frequency full duplex self-interference offset method in multi-path environment

Abstract: The invention discloses a simultaneous common-frequency full duplex self-interference offset method in a multi-path environment. The method comprises the steps that in the transmission end, a digital signal to be transmitted is sent to a signal pre-correction module and a digital interference offset module, and a radio frequency signal to be transmitted is sent to a radio frequency interference reconstruction unit. The signal outputted by the signal pre-correction module passes through a DAC (digital-to-analog converter) and a transmission radio frequency channel to form a pre-corrected radio frequency signal. In the receiving end, the outputted self-interference signal subtracts the pre-corrected radio frequency signal and the radio frequency signal processed by the radio frequency interference reconstruction unit, the radio frequency self-interference offset is finished, and the offset signal, the pre-corrected radio frequency signal and the converted digital signal are sent to the digital interference offset module to finish the digital interference offset, together with the digital signal to be transmitted and the pre-corrected digital signal. The simultaneous common-frequency full duplex self-interference offset method under the multi-path environment is applicable to a simultaneous common-frequency system, the utilization rate of spectrum is doubled, the radio frequency self-interference offset performance is improved, the communication quality of the system is improved, and the working stability of communication equipment in a simultaneous common-frequency multi-path environment is improved.

Multichannel Sampling of Signals Band-Limited in Offset Linear Canonical Transform Domains

Abstract: The aim of the multichannel sampling is the reconstruction of a band-limited signal f(t), from the samples of the responses of M linear time invariant systems, each sampled by the 1/Mth Nyquist rate. As the offset linear canonical transform (OLCT) has been found wide applications in signal processing and optics fields, it is necessary to consider the multichannel sampling based on offset linear canonical transform. In this paper, we develop a multichannel sampling theorem for signals band-limited in offset linear canonical transform domains. Moreover, by designing different OLCT filters, reconstruction formulas for uniform sampling from the signal, from the signal and its first derivative or its generalized Hilbert transform are obtained based on the derived multichannel sampling theorem. Since recurrent nonuniform sampling for the signal has valuable applications, reconstruction expression for recurrent nonuniform samples of the signal band-limited in the offset linear canonical transform domain is also obtained by using the derived multichannel sampling theorem and the properties of the offset linear canonical transform.

Passive Temporal Offset Estimation of Multichannel Recordings of an Ad-Hoc Microphone Array

Abstract: In recent years ad-hoc microphone arrays have become ubiquitous, and the capture hardware and quality is increasingly more sophisticated. Ad-hoc arrays hold a vast potential for audio applications, but they are inherently asynchronous, i.e., temporal offset exists in each channel, and furthermore the device locations are generally unknown. Therefore, the data is not directly suitable for traditional microphone array applications such as source localization and beamforming. This work presents a least squares method for temporal offset estimation of a static ad-hoc microphone array. The method utilizes the captured audio content without the need to emit calibration signals, provided that during the recording a sufficient amount of sound sources surround the array. The Cramer-Rao lower bound of the estimator is given and the effect of limited number of surrounding sources on the solution accuracy is investigated. A practical implementation is then presented using non-linear filtering with automatic parameter adjustment. Simulations over a range of reverberation and noise levels demonstrate the algorithm's robustness. Using smartphones an average RMS error of 3.5 samples (at 48 kHz) was reached when the algorithm's assumptions were met.

Same-time same-frequency full duplex multi-tap radio frequency self-interference offset system and method

Abstract: The invention discloses a same-time same-frequency full duplex multi-tap radio frequency self-interference offset system and method. A wireless unit receiving end outputs self-interference signals, self-interference offset is not conducted at first, after being processed by a radio frequency receiving channel and an analog-digital converter, the self-interference signals are sent to a pattern recognition module to generate an adjustment value, multiple taps are controlled to interfere in a reconstruction filter to reconstruct sending end radio frequency signals in a radio frequency mode, radio frequency self-interference offset is conducted on output reconstruction signals through a summator, signals after the radio frequency self-interference offset are sent to an adjustment algorithm module again through the radio frequency receiving channel and the analog-digital converter to obtain digital signals which are sent to the adjustment algorithm module, an adjusting value needed for adjusting the time delay zero is obtained, radio frequency interference reconstruction is further controlled, controlling over the radio frequency interference reconstruction is carried out repeatedly according to the method, and self-interference offset is achieved. According to the same-time same-frequency full duplex multi-tap radio frequency self-interference offset system and method, joint control of the pattern recognition module and the adjustment algorithm module is used, same-time same-frequency-radio self-interference can be removed effectively, the frequency spectrum utilization rate is improved, the radio frequency self-interference offset performance is improved, and the working stability of communication equipment is guaranteed.

Performance assessment of aided Global Navigation Satellite System for land navigation

Abstract: Land navigation includes the methods to determine the time varying position and velocity of a moving object on Earth surface using suitable measurements; it is typically performed in signal-degraded environments where GPS signals are blocked or degraded; hence GPS-only cannot guarantee an accurate and continuous positioning. The multi-constellation approach is a possible way to fill this gap. In this work GPS/GLONASS systems are combined and single point algorithm performance is assessed for different configurations in urban scenario. GLONASS is nearly fully operational and its inclusion guarantees satellite availability improvement, but the GPS/GLONASS multi-constellation use involves the addition, as further unknown, of the intersystem time-scale offset. The considered estimation techniques are Least Squares and Kalman filter. The first method uses only the measurement model, with the drawback of solution unavailability during GNSS outages. The last uses, in addition to a measurement model, a process model allowing the estimation of the unknowns in case of GNSS outage. To improve both methods performances aiding are considered on height and intersystem time scale offset. The main purposes of this work are the performance assessment of a multi-constellation system relative to GPS-only, adopting the aforesaid estimators, and the benefit evaluation of the aiding.

Devices and methods for sample adaptive offset coding and/or selection of edge offset parameters

Abstract: In one embodiment, a method for encoding sample adaptive offset (SAO) values in a video encoding process is provided, the method comprising: selecting an edge offset type; selecting one of one or more edge offset sub-classes; within at least one of the edge offset sub-classes, generating an interpolated pixel value that is related to a current pixel value; generating an offset value that is related to the interpolated pixel value; and optionally applying the offset value to at least the current pixel value to form an SAO compensated value.

Detection of Vowel Offset Point From Speech Signal

Abstract: Vowel regions play important role in various speech tasks, such as speech segmentation, speaker-verification, prosody modification and emotion conversion. The instants at which the onset and offset of vowel take place in the speech signal are known as vowel onset point and vowel offset point, respectively. Vowel regions start with the vowel onset point and end with the vowel offset point. In this letter, we have proposed two methods for determining the vowel offset points from the speech signal. The first method explores the combination of evidences from excitation source, spectral peaks and modulation spectrum for determining the vowel offset point. In the second method, spectral energy within glottal closure region is used for determining the vowel offset point. The proposed vowel offset point detection methods are evaluated on TIMIT database under clean and noisy environments.

A gray-box neural network-based model identification and fault estimation scheme for nonlinear dynamic systems

Abstract: A novel gray-box neural network model (GBNNM), including multi-layer perception (MLP) neural network (NN) and integrators, is proposed for a model identification and fault estimation (MIFE) scheme. With the GBNNM, both the nonlinearity and dynamics of a class of nonlinear dynamic systems can be approximated. Unlike previous NN-based model identification methods, the GBNNM directly inherits system dynamics and separately models system nonlinearities. This model corresponds well with the object system and is easy to build. The GBNNM is embedded online as a normal model reference to obtain the quantitative residual between the object system output and the GBNNM output. This residual can accurately indicate the fault offset value, so it is suitable for differing fault severities. To further estimate the fault parameters (FPs), an improved extended state observer (ESO) using the same NNs (IESONN) from the GBNNM is proposed to avoid requiring the knowledge of ESO nonlinearity. Then, the proposed MIFE scheme is applied for reaction wheels (RW) in a satellite attitude control system (SACS). The scheme using the GBNNM is compared with other NNs in the same fault scenario, and several partial loss of effect (LOE) faults with different severities are considered to validate the effectiveness of the FP estimation and its superiority.

Fast sample adaptive offset encoding algorithm for HEVC based on intra prediction mode

Abstract: This paper presents a fast sample adaptive offset (SAO) encoding algorithm in High Efficiency Video Coding (HEVC). The key idea of a proposed method is to simplify decision of the best SAO edge offset class by exploiting intra prediction mode information instead of exhaustive RD cost calculation for all classes. The proposed method reduces SAO encoding time about 77.3% only with 0.8% BD-rate degradation under common test condition of HEVC reference software version 10.0.